This study investigates walking in preterm, high-risk but appropriate weight for gestational age infants who will be studied after they have achieved independent ambulation, specifically a group of children which gestational age between 25 and 37 weeks. The gait parameters measured will include rotations of the lower extremity, joints in the sagittal, frontal, and transverse planes; linear measurements, electromyograms, and force plate measurements. These measurements will be carried out in both lower extremities throughout a walking cycle using high speed movies, a Graf/pen sonic digitizer, a computer, and a plotter. The gait parameters of the preterm high-risk infants will be compared with full-term children of identical age between 1 and 7 years. The results of the study of normal children are currently available through a research effort carried out in our laboratory. There are two primary purposes in the study. The first is to evaluate gait analysis as a tool for early identification of neuromuscular impairment in this subject population. The second is to seek correlations between risk factors, specific treatment regimens carried out in the Intensive Care Units and identifiable gait abnormalities. The significance is that early recognition of an abnormality will hasten the implementation of habilitation programs. Information derived from this study will aid in the assessment of risk factors and treatment programs and aid in both economic projections and medical treatment aspects of health care planning.